It has long been known that treatment of tooth surfaces with fluorides has a caries-inhibiting effect. To obtain this effect, fluoride compounds have been incorporated into dentifrices. However, a dentifrice containing a soluble fluoride and calcium carbonate as the abrasive loses an appreciable amount of available fluorine in the composition upon aging. It has been found that the calcium containing abrasive removes the soluble fluoride from the composition by forming insoluble and inactive calcium fluoride (CaF.sub.2), thereby reducing the anticariogenic effectiveness of the fluoride dentifrice.
It is, therefore, an object of this invention to provide dentifrice compositions containing a source of soluble fluoride and calcium carbonate abrasive with improved levels of soluble fluoride availability maintained over a prolonged period of time.